Aldan Shield () is a

shield A shield is a piece of personal armour held in the hand, which may or may not be strapped to the wrist or forearm. Shields are used to intercept specific attacks, whether from close-ranged weaponry like spears or long ranged projectiles suc ...

Siberia Siberia ( ; , ) is an extensive geographical region comprising all of North Asia, from the Ural Mountains in the west to the Pacific Ocean in the east. It has formed a part of the sovereign territory of Russia and its predecessor states ...

. It is an exposed

basement A basement is any Storey, floor of a building that is not above the grade plane. Especially in residential buildings, it often is used as a utility space for a building, where such items as the Furnace (house heating), furnace, water heating, ...

of the

Siberian Craton Siberia, also known as Siberian Craton, Angaraland (or simply Angara) and Angarida, is an ancient craton in the heart of Siberia. Today forming the Central Siberian Plateau, it formed an independent landmass prior to its fusion into Pangea during ...

. Together with the Anabar Shield further to the northwest, the Aldan Shield is one of the main features of the

craton A craton ( , , or ; from "strength") is an old and stable part of the continental lithosphere, which consists of Earth's two topmost layers, the crust and the uppermost mantle. Having often survived cycles of merging and rifting of contine ...

. The Aldan Shield geological region coincides geographically with parts of the Aldan Highlands and Olyokma-Chara Plateau, located at the southern end of the

Sakha Republic Sakha, officially the Republic of Sakha (Yakutia), is a republics of Russia, republic of Russia, and the largest federal subject of Russia by area. It is located in the Russian Far East, along the Arctic Ocean, with a population of one million ...

and the eastern end of

Irkutsk Oblast Irkutsk Oblast (; ) is a federal subjects of Russia, federal subject of Russia (an oblast), located in southeastern Siberia in the basins of the Angara River, Angara, Lena River, Lena, and Nizhnyaya Tunguska Rivers. The administrative center is ...

Google Earth Google Earth is a web mapping, web and computer program created by Google that renders a 3D computer graphics, 3D representation of Earth based primarily on satellite imagery. The program maps the Earth by superimposition, superimposing satelli ...

The exposed crust parts of the shield date back to the

Archean The Archean ( , also spelled Archaean or Archæan), in older sources sometimes called the Archaeozoic, is the second of the four geologic eons of Earth's history of Earth, history, preceded by the Hadean Eon and followed by the Proterozoic and t ...

and reflect the first phases of accretion of the crust. They only emerge in a few areas, the eastern and northern sectors of the shield being largely covered by sediments accumulated between the end of the

Precambrian The Precambrian ( ; or pre-Cambrian, sometimes abbreviated pC, or Cryptozoic) is the earliest part of Earth's history, set before the current Phanerozoic Eon. The Precambrian is so named because it preceded the Cambrian, the first period of t ...

and the

Cambrian The Cambrian ( ) is the first geological period of the Paleozoic Era, and the Phanerozoic Eon. The Cambrian lasted 51.95 million years from the end of the preceding Ediacaran period 538.8 Ma (million years ago) to the beginning of the Ordov ...

, while in the western and southern regions they have undergone processes of tectonic rejuvenation that have brought about the formation of new structures above and below.Siberian craton - a fragment of a Paleoproterozoic supercontinent
/ref> On the Aldan Shield there is the only charoite deposit known in the world - the Sirenevyi Kamen (Lilac Stone) of the Murun Massif. Many other rare and unusual minerals occur in the area of the shield, such as

brookite Brookite is the Orthorhombic crystal system, orthorhombic variant of titanium dioxide (TiO2), which occurs in four known natural Polymorphism (materials science), polymorphic forms (minerals with the same composition but different structure). The ...

, frankamenite, tausonite and yuksporite.Geochronology of the Malyy (Little) Murun Massif, Aldan Shield of the Siberian Craton: A Simple Story for an Intricate Igneous Complex
/ref>

References

External links

Early precambrian A-granitoids in the Aldan Shield and adjacent mobile belts: Sources and geodynamic environmentsArchean crustal evolution of the Aldan Shield, Siberia: Geochemical and Isotopic ConstraintsTrace Element and Sr–Pb–Nd–Hf Isotope Evidence for Ancient, Fluid-Dominated Enrichment of the Source of Aldan Shield Lamproites
{{Coord, 58, 30, N, 125, 30, E, source:ruwiki_region:RU_type:geology, format=dms, display=title Geology of the Sakha Republic Proterozoic Archean Shields (geology)

See also

References

External links